diff --git a/libs/ecs/include/psemek/ecs/entity_container.hpp b/libs/ecs/include/psemek/ecs/entity_container.hpp
index a3c32b1c..e2dc6c81 100644
--- a/libs/ecs/include/psemek/ecs/entity_container.hpp
+++ b/libs/ecs/include/psemek/ecs/entity_container.hpp
@@ -37,6 +37,18 @@ namespace psemek::ecs
 		// or if the entity isn't active
 		entity_accessor get(entity_handle const & entity);
 
+		// Attach new components to an existing entity
+		// If the entity already has a component, its value
+		// is replaced with a new one
+		// TODO: implement
+		template <typename ... Components>
+		void attach(entity_handle const & entity, Components && ... components);
+
+		// Remove components from an existing entity
+		// TODO: implement
+		template <typename ... Components>
+		void detach(entity_handle const & entity);
+
 		// Create a query cache that can be used for the
 		// apply() call to speed it up
 		template <typename ... Components>